“We do know that they were both going east, they were both going in the same direction, and somewhere they collided and separated and one hit a tree and became engulfed,” said Philadelphia Police Capt. John Wilczynski.

The impact caused the car to catch fire. Officials say a pregnant woman inside the car was killed while the male driver suffered a broken hip. Police also say a child was in the backseat of the car but did not suffer any serious injuries.

Investigators say the other car in the right lane swerved to avoid the accident, leading to another crash. There were three people inside the second car, according to investigators. A woman and child inside the car were both taken to the hospital for observation.

Police said speed and possible drag racing were being looked at at possible causes for the wreck.